1. Field of the Invention
This invention relates generally to pneumatic tube systems for transporting carriers and more specifically to those systems which transport carriers between operating zones.
2. Discussion of the Relevant Art
Pneumatic carrier transport systems include at least two stations where carriers can be input to the system and received from the system. In a simple system, pneumatic power provides a fluid pressure or fluid vacuum at each of the stations. This pneumatic power is applied to a tube system which interconnects the stations. In a typical operation, a carrier is inserted into the tube system at one of the stations. Pressure is applied behind the carrier or vacuum is applied in front of the carrier in order to move the carrier through a distribution tube from the initial station to the ultimate station.
In more complex systems, many stations are divided into individual zones. A head diverter associated with each of the zones is in turn coupled through an associated secondary diverter which accesses the other zones. For example, a carrier initially input at a sending zone is held in a stopping chamber and then introduced through the head diverter associated with the sending zone. From the head diverter, the carrier is passed to a secondary diverter also associated with the sending zone and transported to a secondary diverter associated with the receiving zone. The carrier is then transported between the secondary diverter and the head diverter at the receiving zone.
In such a system it can be appreciated that numerous zones can be accommodated, but only with a vast amount of equipment including stopping chambers, head diverters, and secondary diverters. In addition, various slide gates and/or relief valves are required in this type of system. As a consequence, the cost of this system, merely based on the equipment requirements, is significant. Furthermore, the size of the hardware is relatively large and may require as much as 1,000 square feet merely to accommodate a simple six-zone system. Since these systems are commonly used in hospitals and other expensive environments, square footage is at a premium and merely increases the cost of these large systems. The large equipment requirements also result in high maintenance and operation costs.
The complexity of this system and the amount of time required to accomplish the various transmission steps, significantly reduces the overall throughput of the system. This throughput is further reduced by the fact that interzone connections are dedicated between each pair of connecting zones.
In accordance with the present invention, a single rotary carrier distributor is connected to distribution tubes which lead directly to the individual zones. Thus a single distributor might include six separate tubes each communicating with one of six separate zones of the system. Within the distributor each of these zone distribution tubes is coupled through a rotary receiver valve to a rotatable interzone storage device including for example, twelve non-dedicated storage containers.
During operation of the distribution, a carrier may be received through one of the distribution zone tubes and input, with appropriate valving and pneumatic control, into one of the storage containers. The storage device is then rotated to bring the particular storage container into alignment with the distribution tube associated with the receiving zone. Again with appropriate valving and pneumatic control, the carrier is moved from the storage container and into the distribution tube associated with the receiving zone.
Initially it will be noted that the single distributor is the only equipment required for the accommodation of all of the zones. A reduction in the amount of equipment required for distribution is particularly apparent in the initial cost of the distributor. A reduction in the required equipment also results in lower maintenance and operational costs. The single distributor occupies a significantly reduced square footage of space, for example 300 square feet in the case of a six-zone distributor.
With a reduction in the complexity of the equipment, this greatly increases the throughput of the system. Future expansion is also facilitated by this system which accommodates the addition of further distributors with minimum modification.
In comparison to the systems of the past, it will be noted that equipment relating to stopping chambers, slide gates, relief valves, head diverters and secondary diverters is not required.
These and other features and advantages of the invention will become more apparent with a description of preferred embodiments and reference to the associated drawings.